REYMSA COOLING TOWERS, INC.
www.reymsa.com
The
All-Fiberglass
Cooling Towers
65
Operation
C.5. COLD WEATHER OPERATION
Units installed in a cold weather operation environment must use a freezing protection system; Cooling Tower
operates in ambient temperatures 32°F or below there is a risk of the Tower’s water freezing. Build-up of
ice can strongly affect air flow and lead to components failure.
If the Cooling Tower will operate in a freezing climate, take into account the following precautions to help
lessen the chances of damaging property due to freezing water:
▪ Assure adequate air flow; risk of recirculation must be minimized. Recirculation can result in inlet louvers
and fan freezing.
▪ Drain water from the Tower when not in service for any extended period of time.
▪ All external piping that is not drained must be heat traced and insulated, as well as system accessories
like water level control, make-up water valve, spray pump, etc.
▪ Maintain the highest water temperature in the Tower system that will satisfy the cooling load. Outlet
water temperature must be maintained at a minimum of 40ºF. The higher the water temperature is, the
lower the ice formation potential.
▪ Reduce Tower temperature by cycling fans, cycle the fans off or modulate fan speeds (no lower than
50%) to maintain water temperature above freezing. Do not operate fans with air temperatures below
freezing. It is recommended the use of a variable frequency drive (VFD) to allow the closest control of
the leaving water temperature and the fan speed (refer to section “C.1 FAN CONTROL - VFD).
▪ When using a VFD, it is recommended that the minimum speed be set at 50% of full speed to minimize
ice formation. Low leaving water temperature and low air velocity through the unit can cause ice
formation.
▪ Inspect frequently the Tower and the area around the Tower for unacceptable amounts of ice formation.
If ice formation is found, determine where the water is coming from and take corrective action.
▪ A simple way to manage ice build-up is cycling off the fan motors while keeping the pump on. During
a period of fans idle operation, warm water is entering and flows over the unit and helps melt the ice
that has formed in the fill, basin or louver areas.
If fan motors are cycling (ON-OFF) at full voltage controlled by temperature signal
or heat load demand. Rapid ON-OFF cycles can damage the fan.
WARRANTY VOID
FAN MOTOR
Use a soft-starter or VFD as motor starter.
When using a Variable Frequency Drive (VFD), is not uncommon to exhibit resonant
frequencies that result in vibrations, damaging all components of the system. To prevent
premature failure, the VFD must be programed to “skip” resonant frequencies that cause
unusual rumbling or grinding noise.
WARNING
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